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Topeka, KSU students to turn vehicle into one powered by compressed natural gas

About 80 percent of methane created at wastewater plant is wasted

Fire emits from a pipe that expels excess methane generated from the Oakland Wastewater Treatment Plant, 1115 N.E. Poplar. The plant currently wastes 80 percent of the methane it collects -- the equivalent of 1,200 gallons of gasoline each day. The city of Topeka is teaming up with Kansas State University mechanical engineering students to convert one of the city's vehicles into a vehicle powered by compressed natural gas -- an alternative fuel that can be created from methane.

A ground-level look at the anaerobic digesters at the Oakland Wastewater Treatment Plant, 1115 N.E. Poplar, that convert human solid waste into compost and methane. The plant currently wastes 80 percent of the methane it collects -- the equivalent of 1,200 gallons of gasoline each day. The city of Topeka is teaming up with Kansas State University mechanical engineering students to convert one of the city's vehicles into a vehicle powered by compressed natural gas -- an alternative fuel that can be created from methane.

An above-ground look at the anaerobic digesters at the Oakland Wastewater Treatment Plant, 1115 N.E. Poplar, that convert human solid waste into compost and methane. The plant currently wastes 80 percent of the methane it collects -- the equivalent of 1,200 gallons of gasoline each day. The city of Topeka is teaming up with Kansas State University mechanical engineering students to convert one of the city's vehicles into a vehicle powered by compressed natural gas -- an alternative fuel that can be created from methane.

A view of the solid waste extracted from Topeka's wastewater stream that is being converted into compost and methane at the Oakland Wastewater Treatment Plant, 1115 N.E. Poplar. The plant currently wastes 80 percent of the methane it collects -- the equivalent of 1,200 gallons of gasoline each day. The city of Topeka is teaming up with Kansas State University mechanical engineering students to convert one of the city's vehicles into a vehicle powered by compressed natural gas -- an alternative fuel that can be created from methane.

By May, one of the city of Topeka’s vehicles will be able to run on human waste — though converting the matter to usable fuel is a whole other mess.

The city is teaming up with engineering students at Kansas State University to help turn one of its fleet into a vehicle powered by compressed natural gas — an alternative fuel that can be created from the methane extracted from human waste.

For the next semester, about six mechanical engineering students in their senior design class will convert the city’s vehicle to CNG in an attempt to find a use for methane gas generated — and largely wasted — at the Oakland Wastewater Treatment Plant, 1115 N.E. Poplar. Each year, the plant wastes the methane equivalent of about 440,000 gallons of gasoline, said public works utilities infrastructure division director Don Rankin.

For the K-State project, Topeka will be on the line for supplying the vehicle — likely an older city dump truck — and purchasing parts to make the conversion. Rankin said he doesn’t expect to spend more than $10,000 on the project.

The city will save money by having students complete the conversion, and the students will benefit from a hands-on, real-life experience, he said. But he also is excited to see what the students will do.

“Students come up with crazy ideas,” Rankin said. “Sometimes they stumble onto things other people haven’t thought up yet because they don’t have bosses telling them no.”

The results and pending cost benefit analysis could go a long way in helping the department determine the best use for the wasted fuel — a goal included in its 2014 Capital Improvement Plan, Rankin said.

Any proposals to expand the CNG program — or more feasible uses for the methane — wouldn’t go before the Topeka City Council until later this year at the earliest, he said.

Converting even some of the city’s fleet into CNG-powered vehicles would be a costly endeavor.

Building a plant to convert methane to CNG alone would cost upward of $2 million, Rankin said. Then the city would have to convert its vehicles to CNG — several thousand dollars each — and establish fueling stations around the city to make it practical, Rankin said. He currently is talking with Kansas Gas Service about a potential partnership for the latter piece, he added.

However, Rankin said, with the ever-rising price of gas and comparable efficiency of CNG fuel, the city could see significant savings down the road. It also would help reduce the city’s pollution twofold, both from vehicles and the wastewater plant.

“Burning methane may not sound clean, but it is fairly clean,” he said.

Currently, the Oakland plant uses about 20 percent of the methane it makes to heat the very equipment that creates the methane and compost. The remaining 80 percent, which is released into the atmosphere, could provide the equivalent of 1,200 gallons of fuel each day.

For perspective, the Oakland Wastewater fleet uses about 150,000 gallons a year, Rankin said. That would leave nearly 290,000 gallons a year to power other CNG-powered vehicles.

If the project goes anywhere, he said, he would advocate that CNG conversions start with the larger vehicles that get 4 miles to the gallon, because they are more costly to run on gasoline.